In 1941, they knew

On this day in 1941, even before the Germans had officially decided to do it, Abba Kovner warned fellow residents of the Vilna Ghetto that the Germans planned to wipe out European Jewry.

On December 31, 1941, Abba Kovner spoke before an assembly
of Vilna Ghetto youth and declared his far-sighted and far from
conventional conviction that the Nazis were determined “to destroy all
the Jews